Fuse



March 6, 1951 J SCHERMULY 2,544,358

FUSE

Filed Dec. 22, 1948 ALFRED JA M55 HER/Mr BY HIS A TTORNEYJ Patented Mar. 6, 1951 FUSE Alfred James Schermuly, Parkga-te, Newdigate,

England Application December 22, 1948,.Serial No. 66,647 In GreatBritain J anllary 2, .1948

This invention relates to fuzes for the ignition of pyrotechnic devices, such as flares and the like, which are dropped from aircraft and has for its object to provide a fuze which is not actuated until after the device has left the aircraft.

The usual method of igniting fiares to be dropped from aircraft is by means of a friction or percussion igniter connected to a delay fuze within the flare casing, the igniter being actuated prior to dropping the flare. It has been found in practice that it is possible for the flare to become ignited before leaving the aircraft with consequent danger of fire in the aircraft.

According to the present invention a fuze for pyrotechnic devices to be dropped from aircraft comprises a cruciform member having a hollow body and two aligned hollow arms, the passage through said hollow arms intersecting the passage through the body, a sliding member in said hollow body, a screw cap adapted to hold the said sliding member in a position to obstruct the passage through said arms, in opposition to a spring, a firing pin within one of said hollow arms, a spring loaded detonator in the other of said hollow arms, and vanes on said cap which during the fall of the device unscrew the cap to release the sliding member and thereby allow unobstructed movement of the detonator onto the firing The invention will now be described by way of example with reference to the accompanying drawings in which,

Figure 1 is an exploded view of a fuze according to this invention.

Figure 2 is a section through the fuze in safe position, the vanes on the cap having been omitted, and

Figure 3 is a similar section through the fuze after it has been fired.

Referring to the drawings, a cruciform member consisting of a tubular body I and tubular arms 2, 3 is provided with an external screwthread 4 by means of which it may be screwedinto the nose of the casing of a pyrotechnic device, such as a flare, external screw-threads 5 and 6 onto which knurled caps I and 8 may be screwed, and a screwthread 9 onto which a cuplike member I may be screwed.

The passage II through the body I has a widened portion I2. The body I is adapted to contain a sliding member I3 comprising a stem I 4 which is a sliding fit in the passage II and a flange I which is a sliding fit in the widened 5 Claims. (Cl. 102-86) portion I2. A spring I6 is arranged around the stem M.

The cup-lik member ID is provided with an internal screwthread I'I adapted to engage the screwthread 9 on the "body I. The base of the cup-like member ID is provided with a screwed hole I8.

The cap I9, having vanes 20, is provided with a central peg 2|, the lower part of which is externally screwthreaded for engagement in the screwed hole I8.

The knurled cap I is provided with a firing pin 22, and the knurled cap 8 is adapted to retain a detonator 23 and a spring 24 within the arm 3.

A safety pin 25 and a spring clip 26 are also provided.

The procedure for assembling the fuze is as follows:

The sliding member I3 and spring I6 are inserted in the body I and the cup-like member ID screwed on. The cap I9 is then screwed on, whereby the peg ZI forces the sliding member I3 into the position shown in Figure 2. In this position the safety pin 25 may be passed through holes in the cap 20, the cup-like member ID and the peg 2I, and held in position by means of the spring clip 26. This holds these parts against unintentional rotation. It is preferable that the screwthreads 9 and I8 should be in opposite directions, one right-hand and the other left-hand.

The detonator 23 and spring 24 are then inserted inside the arm 3 and the knurled cap 8 is screwed on. The detonator 23 is thus held firmly pressed by the spring 24 against the stem I4.

The knurled cap I is then screwed on, and the fuze screwed by means of the screwthread 4 into the nose of the casing of a pyrotechnic device, such as a fiare.

When the pyrotechnic device is to be used, the safety pin 25 is removed and the device dropped from the aircraft. During the first part of its fall, the vanes 2|] rotate the cap I9, thereby unscrewing it from the screwed hole I8, whereupon the cap I9 falls away and the spring I6 is then able to urge the sliding member I3 into the position shown in Figure 3. The spring 24 then forces the detonator 23 into engagement with the firing pin 22 and the flash from the detonator passes through the passage I I to ignite either the device or a delay fuze connected to the device.

It will be observed that the arming of the fuze takes place while the device is dropping through the air, and premature ignition of the device within the aircraft with consequent danger of fire, is impossible.

I 3 What I claim is: s 1. A fuze for pyrotechnic devices to be dropped from aircraft, comprising a cruciform member having a hollow body and two aligned hollow arms, the passage through said hollow arms intersecting the passage through the body, a sliding member in said hollow body, a cap having a central peg which is adapted to hold the said sliding member in a position to obstruct the passage through said arms in opposition to a spring, a cup-like member having a threaded hole in its base, said cup-like member being screwed on to said hollow body and said peg being screwed into the hole in the cup-like member, a firing pin within one of said hollow arms, a spring loaded detonator in the other of said hollow arms, and vanes on said cap which during the fall of the device unscrew said peg from the cup-like member to release the sliding member and thereby allow unobstructed movement of the detonator on to the firing pin. 7 a

2. A fuze as claimed in claim 1 wherein the passage in the hollow body has a widened portion and the sliding member comprises a stem which is a sliding fit in the narrower portion of 25 said passage and a flange which is a sliding fit in said widened portion.

3. A fuze as claimed in claim 2 in which a spring is coiled around said stem.

4. A fuze as claimed in claim 3 there being apertures adapted to receive a safety pin in the body and the cap to prevent premature rotation of the cap.

5. A fuze as claimed in claim 4 in combination with a second cap adapted to be screwed on to one of said arms, the firing pin being mounted in said second threaded cap.

ALFRED JAMES SCHERMULY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Nov. 21, 1946 

